package com.ysq.filter;

import com.alibaba.fastjson.JSON;
import com.ysq.common.BaseContext;
import com.ysq.controller.result.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * ClassName: LoginFilter
 * Package: com.ysq.filter
 * Description:
 *
 * @Author YSQ
 * @Create 2023/1/2 - 10:03
 */
@Slf4j //输出日志用于测试
@WebFilter(filterName = "loginFilter", urlPatterns = "/*") //配置拦截路径, 全部拦截
public class LoginFilter implements Filter {
    //路径匹配器, 支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //把request和response向下强转
        HttpServletRequest request = (HttpServletRequest) servletRequest;//获取URI
        HttpServletResponse response = (HttpServletResponse) servletResponse;//向前端响应数据

        //1. 获取本次请求的URI
        String requestURI = request.getRequestURI();
        log.info("拦截到请求：{}", requestURI);
        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",// 登录请求
                "/employee/logout",// 退出请求
                "/backend/**",// 静态资源
                "/front/**",// 静态资源
                //要想识别** 需要支持通配符的路径匹配器AntPathMatcher
                "/user/login",//用户登录操作
                "/user/sendMsg"//邮箱发送验证码请求
        };


        //2. 判断本次请求是否需要处理
        boolean check = check(urls, requestURI);

        //3. 如果不需要处理，则直接放行
        if(check){
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(request, response);//放行
            return;
        }

        //4-1. 判断后台登录状态，如果已登录，则直接放行
        //因为之前登录成功会在session存数据, 所以直接查看session中有没有数据即可判断是否登录成功
        if(request.getSession().getAttribute("employee") != null){
            log.info("用户已登录，用户id为：{}", request.getSession().getAttribute("employee"));
            Long empId = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);
            filterChain.doFilter(request,response);//放行
            return;
        }
        //4-2. 判断用户登录状态
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));
            Long userId = (Long)request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);
            filterChain.doFilter(request,response);//放行
            return;
        }

        //5. 如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        log.info("用户未登录");
        response.getWriter().write(JSON.toJSONString(Result.error("NOTLOGIN")));
    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls 不需要处理的请求URI
     * @param requestURI 本次请求的URI
     * @return 匹配上返回true代表不需要处理, 返回false代表需要处理这次请求
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if(match){
                return true;
            }
        }
        return false;
    }
}
